Jor-El's history seems to get retconned in the comics every few years, but it's generally accepted that Jor-El was one of the greatest scientists on Krypton. He discovered the Phantom Zone and invented the Phantom Zone Projector, which teleported people into that interdimensional prison. For these accomplishments, he was given a seat on the Science Council, Krypton's ruling body. He's generally depicted as the person who sent the Kryptonian rebels General Zod, Ursa, and Non into the Phantom Zone. Jor-El determined that Krypton was doomed to be destroyed, but his warnings were ignored by other Kryptonians. He created a homemade rocketship and was able to save his son Kal-El by placing him in the ship and sending him off into the aether just before Krypton exploded.

Superman has met Jor-El several times, either through holographic projections in his Fortress of Solitude or through time travel back to pre-destruction Krypton. He's certainly had more impact on the Superman mythos than Kal-El's mother Lara, who nearly always gets ignored or given short shrift by the character's writers. Jor-El remains, nevertheless, an important touchstone for Superman's past, and his drive to save Krypton and willingness to sacrifice himself for his son can be seen as inspirational forces for his son's future career as a superhero.